WO2022047681A1 - Procédé de préparation de mdi et procédé de préparation de phosgène - Google Patents

Procédé de préparation de mdi et procédé de préparation de phosgène Download PDF

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WO2022047681A1
WO2022047681A1 PCT/CN2020/113112 CN2020113112W WO2022047681A1 WO 2022047681 A1 WO2022047681 A1 WO 2022047681A1 CN 2020113112 W CN2020113112 W CN 2020113112W WO 2022047681 A1 WO2022047681 A1 WO 2022047681A1
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catalyst
phosgene
packing section
activated carbon
mass
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PCT/CN2020/113112
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English (en)
Chinese (zh)
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文放
王振有
赵东科
陈良进
徐丹
董超
张宏科
吴雪峰
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万华化学集团股份有限公司
万华化学（宁波）有限公司
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Priority to PCT/CN2020/113112 priority Critical patent/WO2022047681A1/fr
Publication of WO2022047681A1 publication Critical patent/WO2022047681A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/18—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/20—Carbon compounds
    • B01J27/22—Carbides
    • B01J27/224—Silicon carbide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/80—Phosgene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C263/00—Preparation of derivatives of isocyanic acid
    • C07C263/10—Preparation of derivatives of isocyanic acid by reaction of amines with carbonyl halides, e.g. with phosgene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C265/00—Derivatives of isocyanic acid
    • C07C265/14—Derivatives of isocyanic acid containing at least two isocyanate groups bound to the same carbon skeleton

Definitions

  • the invention relates to the technical fields of phosgene preparation and MDI preparation, in particular to a phosgene preparation method capable of reducing trace impurities in phosgene and an MDI preparation method capable of improving the stability of MDI production process.
  • Phosgene is an important raw material in the production process of MDI. Phosgene is obtained by the phosgene synthesis reaction between CO and chlorine under the catalytic reaction of activated carbon.
  • Chinese published patent CN105916810A describes the control method of free chlorine in phosgene and the operation scheme of starting and stopping, but this patent only focuses on the control of free chlorine, and does not involve the control of high-boiling chlorinated hydrocarbons.
  • Chinese patent CN1156393C introduces a method for preparing phosgene with a carbon tetrachloride content of less than 150 ppm, and describes the scheme of the preparation process. Likewise, this document does not recognize the effect of high-boiling substances in chlorides on the reaction yield during the phosgenation reaction.
  • the present invention provides a method for preparing phosgene capable of reducing the impurity content of high-boiling chlorinated hydrocarbons in phosgene and a method for preparing MDI with improved process stability.
  • One aspect of the present invention provides a method for preparing MDI (diphenylmethylene diisocyanate), the method comprising: in the presence of a solvent, phosgene raw material and MDA (diphenylmethylene diamine) are prepared in light
  • a phosgenation reaction is carried out in the gasification reactor to generate a reaction product comprising the MDI and hydrogen chloride, and the hydrogen chloride is discharged from the phosgenation reactor as an external exhaust phase, and all the phosgenation reaction will be used to participate in the phosgenation reaction.
  • the mass content of the chlorinated hydrocarbon impurities contained in the phosgene raw material is controlled to be less than 1000 ppm; the chlorinated hydrocarbon impurities are saturated and/or unsaturated chlorinated hydrocarbons with 2 carbon atoms.
  • the mass content of the above-mentioned chlorinated hydrocarbon impurities contained in the phosgene raw material is, for example, less than 1000 ppm, less than 900 ppm, less than 800 ppm, less than 600 ppm, less than 500 ppm, less than 400 ppm, less than 100 ppm, less than 50 ppm, less than 20 ppm, less than 15 ppm, etc., such as greater than 0.1 ppm and less than 1000 ppm, eg greater than 1.5 ppm and less than 400 ppm.
  • the chlorinated hydrocarbon impurities refer to saturated and/or unsaturated chlorinated hydrocarbons with 2 carbon atoms, and are specifically composed of one or more of the following compounds: ethylene monochloride, ethylene dichloride , trichloroethane, tetrachloroethane, monochloroethylene, dichloroethylene, trichloroethylene, tetrachloroethylene, monochloroacetylene, dichloroacetylene, these impurities are also referred to herein as high boiling point chlorinated hydrocarbon impurities.
  • the above-mentioned chlorinated hydrocarbon impurities contained in phosgene may be constituted by one or more of the specific chlorinated hydrocarbon compounds listed above.
  • the solvent includes one or more of chlorobenzene, dichlorobenzene, and toluene, preferably, the solvent is chlorobenzene.
  • the phosgene is prepared by performing a phosgene synthesis reaction with carbon monoxide and chlorine in the presence of a catalyst in a phosgene synthesis reactor, and a catalyst and an inert filler are loaded in the catalyst loading zone of the phosgene synthesis reactor.
  • the catalyst is composite activated carbon with high thermal conductivity, and the catalyst loading area is divided into a first loading section, a second loading section and a third loading section from bottom to top; based on the catalyst and inert packing in each loading section The total mass of the catalyst in the second packing section is greater than that in the first packing section, and the catalyst mass percentage in the third packing section is greater than that in the second packing section. percentage;
  • the preparation of the high thermal conductivity composite activated carbon includes the following steps: mixing the activated carbon powder, the granular additives and the adhesive with water to make a paste, drying and molding, and then heating the activated carbon powder at 600-800° C. (for example, 600° C., 650° C., 700°C, 750°C, 800°C, etc.) for constant temperature carbonization (for example, the constant temperature carbonization time is more than 2h, such as 2-72h, such as 2h, 4h, 8h, 24h, 48h, 72h, etc.) to obtain the high thermal conductivity composite activated carbon;
  • the mass ratio of the granular additive and the activated carbon powder is (1-10):100 (for example, 1:100, 3:100, 5:100, 7:100, 10:100, etc.), and the granular additive is selected from One or more of alumina ceramic balls, silicon carbide, graphite, and boron carbide.
  • the drying conditions for the drying molding include placing the paste in a constant temperature
  • the above-mentioned high thermal conductivity composite activated carbon is used as a catalyst, and the catalyst is loaded in the catalyst loading area of the phosgene synthesis reactor according to a specific loading method.
  • the reactivity between carbon and chlorine is greatly reduced,
  • the generation of high-boiling chlorinated hydrocarbons (saturated and/or unsaturated chlorinated hydrocarbons with 2 carbon atoms) is reduced, thereby effectively reducing the impurity content of high-boiling chlorinated hydrocarbons in the phosgene synthesis process, and high-boiling chlorinated hydrocarbons can be obtained
  • the phosgene raw material with low impurity content, specifically, the mass content of high-boiling point chlorinated hydrocarbon impurities in the obtained phosgene is less than 1000ppm, such as more than 0.1ppm and less than 1000ppm, such as less than 400ppm, such as more than 1.5ppm and
  • the mass percentage of the catalyst in the first packing section is 0%-50% (for example, 0%, 10%, 20%, 30%, 40%, 50%, etc.)
  • the mass percentage of the catalyst in the second packing section is 20%-80% (for example, 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc.)
  • the mass percentage of the catalyst in the third packing section is 40%-100% (for example, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc.
  • the catalyst mass percentage in the second packing section is greater than the catalyst mass percentage in the first packing section, and the catalyst in the third packing section The mass percentage is greater than the catalyst mass percentage in the second packing section;
  • the height ratio of the first packing section is 10%-40% (for example, 10%, 20%, 30%, 40%, etc.), and the height ratio of the second packing section 10%-80% (such as 10%, 30%, 50%, 80%, etc.), the height ratio of the third filling section is 10-80% (such as 10%, 30%, 50%, 80%, etc.) ).
  • the activated carbon powder and granular additives are mixed in advance to form a paste.
  • a paste is formed by adding an appropriate amount of adhesive and water.
  • the mass ratio of the powder is (3-20):100 (for example, 3:100, 5:100, 10:100, 15:100, 20:100, etc.)
  • the mass ratio of the activated carbon powder to the water is (20 -50):100 (for example, 20:100, 30:100, 40:100, etc.)
  • the adhesive used can be, for example, emulsified phenolic resin, activated clay, emulsified coal tar, carboxymethyl cellulose and the like.
  • the inert filler loaded in the catalyst loading zone is one or more of alumina ceramic balls, spherical silicon carbide, and graphite.
  • the above-mentioned phosgene preparation process is specifically a technical scheme formed on the basis of the existing technology for preparing phosgene by phosgene synthesis reaction under the catalysis of activated carbon based on carbon monoxide and chlorine, mainly in that the existing catalyst is improved and Combined with the specific packing method of the catalyst, the impurity content of high-boiling point chlorinated hydrocarbons in the existing phosgene synthesis reaction can be reduced, and phosgene with a high-boiling point chlorinated hydrocarbon content of less than 1000 ppm can be obtained.
  • other process conditions for the preparation of phosgene corresponding conventional process conditions in the art can be adopted.
  • the pressure is 1 barg-7 barg, preferably 2.5 barg-3.5 barg
  • the phosgene synthesis reactor that is, the phosgene synthesis reaction tower
  • the phosgene synthesis reactor that is, the phosgene synthesis reaction tower
  • the phosgene synthesis reactor that is, the phosgene synthesis reaction tower
  • the volume flow ratio of carbon monoxide and chlorine gas is 100:(85-98).
  • the mass content of the high-boiling chlorinated hydrocarbon impurities in the external exhaust gas phase is less than 800 ppm, such as greater than 0.5 ppm and less than 800 ppm, such as less than 350 ppm , such as greater than 2ppm and less than 350ppm;
  • the mass content of the high-boiling point chlorinated hydrocarbons in the solvent of the reaction system is less than 4%, such as greater than 50 ppm and less than 4%, such as less than 2.5%, For example, more than 100 ppm and less than 2.5%.
  • the method for preparing MDI provided by the present invention is specifically a technical scheme formed by improving the existing technology based on phosgene and MDA for preparing MDI through phosgenation reaction, mainly in that the high boiling point chlorine in the phosgene raw material is treated Substitute hydrocarbon impurity content control, so as to achieve technical effects such as improving the stability of the process.
  • other process conditions of the method for preparing MDI corresponding conventional process conditions in the art can be adopted.
  • the reaction conditions for the phosgenation reaction include: the pressure of the phosgenation reaction is 1 barg-7 barg, preferably 2.5 barg-3.5 barg, and the maximum temperature of the phosgenation reactor is 110 ° C-180 ° C, preferably 125°C-145°C, the mass ratio of pure phosgene participating in the reaction (referring to the phosgene in phosgene solution) to MDA is 1.5-3.0, preferably 2.0-2.5; the MDA and the phosgene are respectively used
  • the solvent is prepared into MDA solution and phosgene solution and put into the reaction system.
  • the MDA mass concentration of the MDA solution is 20%-45%, preferably 30%-40%; the phosgene mass concentration of the phosgene solution is 40%-40%- 90%, preferably 60%-75%.
  • the present invention also provides a method for preparing phosgene capable of reducing the impurity content of chlorinated hydrocarbons in phosgene.
  • the phosgene is prepared by performing a phosgene synthesis reaction with carbon monoxide and chlorine in a phosgene synthesis reactor in the presence of a catalyst,
  • the high thermal conductivity composite activated carbon is used as the catalyst in the phosgene synthesis reactor, the catalyst loading zone of the phosgene synthesis reactor is loaded with a mixture of catalyst and inert filler, and the catalyst loading zone of the phosgene synthesis reactor consists of the following It is divided into a first packing section, a second packing section and a third packing section in sequence; based on the total mass of the catalyst and inert packing in each packing section, the mass percentage of the catalyst in the second packing section is greater than that in all the packing sections.
  • the catalyst mass percentage in the first packing section, the catalyst mass percentage in the third packing section is greater than the catalyst mass
  • the preparation of the high thermal conductivity composite activated carbon includes the following steps: mixing the activated carbon powder, the granular additives and the adhesive with water to make a paste, drying and molding, and then heating the activated carbon powder at 600-800° C. (for example, 600° C., 650° C., 700°C, 750°C, 800°C, etc.) for constant temperature carbonization (for example, the constant temperature carbonization time is more than 2h, such as 2-72h, such as 2h, 4h, 8h, 24h, 48h, 72h, etc.) to obtain the high thermal conductivity composite activated carbon;
  • the mass ratio of the granular additive and the activated carbon powder is (1-10):100 (for example, 1:100, 3:100, 5:100, 7:100, 10:100, etc.), and the granular additive is selected from One or more of alumina ceramic balls, silicon carbide, graphite, and boron carbide; preferably, the drying conditions for the drying molding include placing the paste in a constant
  • the chlorinated hydrocarbon impurities are saturated and/or unsaturated chlorinated hydrocarbons with a carbon number of 2, and such impurities are also referred to herein as high boiling point chlorinated hydrocarbon impurities.
  • the content of the chlorinated hydrocarbon impurities is less than 1000ppm, such as less than 1000ppm, less than 900ppm, less than 800ppm, less than 600ppm, less than 500ppm, less than 400ppm, less than 100ppm, less than 50ppm, less than 20ppm, less than 15ppm, etc. , eg greater than 0.1 ppm and less than 1000 ppm, eg less than 400 ppm, eg greater than 1.5 ppm and less than 400 ppm.
  • the mass percentage of the catalyst in the first packing section is 0%-50% (eg 0%, 10%, 20%, 30%) , 40%, 50%, etc.)
  • the mass percentage of the catalyst in the second packing section is 20%-80% (for example, 20%, 30%, 40%, 50%, 60%, 70%, 80% etc.)
  • the mass percentage of the catalyst in the third packing section is 40%-100% (eg 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc.); and based on each The total mass of the catalyst and the inert filler in the packing section, the mass percentage of the catalyst in the second packing section is greater than the mass percentage of the catalyst in the first packing section, and the mass percentage of the catalyst in the third packing section is greater than the The mass percentage of catalyst in the second packing section; based on the total height of the catalyst packing section, the height ratio of the first packing section is 10%-40% (eg 10%, 20%, 30%, 40%, etc.) , the height ratio of the second fill
  • the mass ratio of the adhesive to the activated carbon powder is (3-20):100 (for example, 3:100, 5:100, 10:100, 15:100, 20:100, etc.), and the The mass ratio of activated carbon powder to the water is (20-50):100 (for example, 20:100, 30:100, 40:100, etc.).
  • the inert filler loaded in the catalyst loading zone is one or more of alumina ceramic balls, spherical silicon carbide, and graphite;
  • the chlorinated hydrocarbon impurities are specifically one or more of the following compounds: a Ethyl chloride, dichloroethane, trichloroethane, tetrachloroethane, monochloroethylene, dichloroethylene, trichloroethylene, tetrachloroethylene, monochloroacetylene, dichloroacetylene.
  • a Ethyl chloride dichloroethane, trichloroethane, tetrachloroethane, monochloroethylene, dichloroethylene, trichloroethylene, tetrachloroethylene, monochloroacetylene, dichloroacetylene.
  • the pressure is controlled to be 1barg-7barg, preferably 2.5barg-3.5barg
  • the phosgene synthesis reactor (phosgene synthesis tower) ) outlet temperature is 30 °C-270 °C, preferably 190 °C-220 °C, and the volume flow ratio of carbon monoxide and chlorine is 100:(85-98).
  • HCS substances high-boiling point chlorinated hydrocarbon impurities
  • the inventors of the present application have found through research that in the process for preparing MDI by using phosgene and MDA through phosgenation reaction, when the high-boiling chlorinated hydrocarbons (saturated and/or non-carbon atoms with 2 carbon atoms) in the raw material phosgene When the content of saturated chlorinated hydrocarbons) is high, the effluent hydrogen chloride cannot bring out the high-boiling point chlorinated hydrocarbons in time, which will cause the high-boiling point chlorinated hydrocarbons to be enriched in the process system, resulting in the composition of the solvent in the reaction system.
  • the inventors of the present application have surprisingly found that in the process of preparing MDI, by using a phosgene raw material whose mass content of high-boiling point chlorinated hydrocarbon impurities is controlled to be less than 1000 ppm to prepare MDI, it is possible to avoid the boiling point of the solvent in the reaction system being at the same level as that of MDI. Large fluctuations occur in the preparation process, thereby helping to ensure a relatively stable product yield, improving the stability of the process production, and extending the process cycle.
  • the mass content of the high-boiling point chlorinated hydrocarbon impurities contained in the phosgene raw material is, for example, greater than 0.1 ppm and less than 1000 ppm; in some embodiments, the mass content of the high-boiling point chlorinated hydrocarbon impurities contained in the phosgene raw material is The mass content is eg less than 400 ppm, eg greater than 1.5 ppm and less than 400 ppm.
  • the lower the mass content of the high-boiling point chlorinated hydrocarbon impurities contained in the phosgene raw material the better.
  • phosgene with low impurity content of high-boiling point chlorinated hydrocarbons can be obtained.
  • the quality of high-boiling point chlorinated hydrocarbon impurities can be obtained.
  • the phosgene raw material with a content of less than 1000 ppm can provide a phosgene raw material with a mass content of high-boiling chlorinated hydrocarbon impurities less than 1000 ppm for the downstream MDI preparation, and improve the process stability of MDI preparation.
  • the yield of the chemical reaction process is affected.
  • the inventors have determined that the content of high-boiling point chlorinated hydrocarbons in phosgene is controlled to be less than 1000 ppm, which can ensure that the boiling point of the solvent will not rise significantly during the production process of phosgene, thereby realizing phosgene.
  • the yield of the chemical reaction process is stable and reaches the expected target.
  • the present invention optimizes, improves and prepares the types of catalysts involved in phosgene synthesis, and obtains a high thermal conductivity composite activated carbon, which is used in the synthesis reaction of phosgene in combination with a specific filling method, which greatly reduces the interaction between carbon and chlorine. Reactive, reducing the formation of high-boiling chlorinated hydrocarbons.
  • the content of the present invention is further described below in conjunction with the examples, but the content of the present invention is not limited to the following examples.
  • the test method of specific conditions is not indicated, and it is generally in accordance with conventional conditions.
  • the “content” involved in the text refers to the mass content unless otherwise specified.
  • Silicon carbide Shanghai Baitu, domestic silicon carbide
  • Emulsified phenolic resin Shanghai Latex Factory, HX30;
  • Activated clay Qingdao Wanhong Mining Co., Ltd.;
  • Activated carbon powder Tsurumi, Japan, 4GV-K.
  • HCS substance saturated/unsaturated chlorinated hydrocarbon impurities with a carbon number of 2, denoted as HCS substance
  • the content of various high-boiling point chlorinated hydrocarbon impurities is obtained by gas chromatography, and the sum of the contents of each high-boiling point chlorinated hydrocarbon impurity is the total content of high-boiling point chlorinated hydrocarbon impurities.
  • phosgene is prepared by using a phosgene synthesis device.
  • the content of hydrocarbons (such as ethane, ethylene, acetylene, etc.) in the introduced CO is less than 1 ppm, and the volume flow ratio of CO to chlorine is 100:93.
  • the operating temperature of the phosgene synthesis (ie the outlet temperature of the phosgene synthesis reactor) is 200°C, the operating pressure is 3.0 barg, the activated carbon is packed in the tube, the diameter of the tube is DN50 (that is, the diameter of the tube is 50mm), and the length of the tube is 5000mm, the catalyst used is 4GV type activated carbon from Tsurumi, Japan, and the inert agent is alumina ceramic balls; the catalyst loading area is divided into three sections from bottom to top, and the loading method is that the height of the first section is 1.0m, mixed with 80wt% oxidation Aluminum ceramic balls, 20wt% activated carbon, the height of the second section is 1.0m, mixed with 40wt% alumina ceramic balls, 60wt% activated carbon, and the third section height is 3.0m, all of which are activated carbon.
  • the content of high-boiling point chlorinated hydrocarbons (HCS substances) in the phosgene produced by phosgene synthesis is detected to be 6520 ppm, and it is continuously sent to the phosgenation reactor to react with MDA to generate MDI.
  • the solvent used in the phosgenation reaction is chlorobenzene.
  • the pressure of the gasification reaction is 3.2 barg
  • the maximum temperature of the phosgenation reactor is 135°C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA mass of the MDA solution (solvent is chlorobenzene) put into the reaction system The concentration was 30%, and the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • the total amount of HCS in chlorobenzene, the solvent used in the phosgenation reaction reached 4%, which caused the boiling point of the solvent to rise from 132 °C to 144 °C, and the phosgenation reaction yield decreased from 99.5%.
  • the system began to show obvious blockage. After 8 months of operation, it had to stop to drain, replace the solvent, and remove the HCS substance in the solvent.
  • This comparative example uses a phosgene synthesis device with by-product steam.
  • the activated carbon is different from that of Comparative Example 1, and the catalyst loading method is the same as that of Comparative Example 1.
  • the content of high-boiling chlorinated hydrocarbons (marked as HCS substances) exceeds the standard.
  • phosgene is prepared by using a phosgene synthesis device.
  • the hydrocarbons in the introduced CO are less than 1 ppm, the volume flow ratio of CO and chlorine is 100:93, and the phosgene synthesis operating temperature (that is, the phosgene synthesis reaction
  • the outlet temperature of the device) is 205 °C, the operating pressure is 3.0 barg, the activated carbon is packed in the tube, the diameter of the tube is DN50, the length of the tube is 5000mm, and the catalyst used is Norit-B type activated carbon from Norit, the Netherlands , the inert agent uses alumina ceramic balls; the catalyst loading area is divided into three sections from bottom to top, the filling method is that the height of the first section is 1.0m, mixed with 80wt% alumina ceramic balls and 20wt% activated carbon, and the height of the second section is 1.0 m. m, mixed with 40wt% alumina ceramic balls and 60wt% activated carbon, the height of the
  • HCS substances high-boiling point chlorinated hydrocarbons
  • the content of high-boiling point chlorinated hydrocarbons (HCS substances) in the phosgene produced by phosgene synthesis is detected to be 7710 ppm, and is continuously sent to the phosgenation reactor to react with MDA to generate MDI.
  • the solvent used in the phosgenation reaction is chlorobenzene.
  • the pressure of the gasification reaction is 3.2 barg
  • the maximum temperature of the phosgenation reactor is 135°C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA mass of the MDA solution (solvent is chlorobenzene) put into the reaction system The concentration was 30%, and the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • the total amount of HCS in chlorobenzene, the solvent used in the phosgenation reaction reached 5.2%, which caused the boiling point of the solvent to rise from 132 °C to 141 °C, and the phosgenation reaction yield decreased from 99.5%.
  • the system began to show obvious blockage. After 7.5 months of operation, the system had to be stopped to drain and replace the solvent to remove the HCS substance in the solvent.
  • This comparative example uses a phosgene synthesis device with by-product steam.
  • the activated carbon is the same as that of Comparative Example 1, and the filling method is different from that of Comparative Example 1.
  • the content of high-boiling chlorinated hydrocarbons (marked as HCS substances) exceeds the standard.
  • phosgene is prepared by using a phosgene synthesis device.
  • the content of hydrocarbons in the introduced CO is less than 1 ppm
  • the volume flow ratio of CO and chlorine is 100:93
  • the phosgene synthesis operating temperature (that is, phosgene synthesis
  • the outlet temperature of the reactor) is 205 ° C
  • the operating pressure is 3.0 barg
  • the activated carbon is packed in the tube
  • the diameter of the tube is DN38
  • the length of the tube is 5000mm
  • the catalyst used is Japan Tsurumi 4GV type activated carbon, inert
  • the catalyst is made of alumina ceramic balls; the catalyst loading area is divided into three sections from bottom to top.
  • the filling method is that the height of the first section is 1.5m, which is mixed with 75wt% alumina ceramic balls and 25wt% activated carbon, and the height of the second section is 1.0m. Mixed with 40wt% alumina ceramic balls and 60wt% activated carbon, the height of the third section is 2.5m, all of which are activated carbon.
  • the content of high-boiling point chlorinated hydrocarbons (HCS substances) in the phosgene produced by phosgene synthesis is detected to be 5500 ppm, and is continuously sent to the phosgenation reactor to react with MDA to generate MDI.
  • the solvent used in the phosgenation reaction is chlorobenzene.
  • the pressure of the gasification reaction is 3.2 barg
  • the maximum temperature of the phosgenation reactor is 135°C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA mass of the MDA solution (solvent is chlorobenzene) put into the reaction system The concentration was 30%, and the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • the total amount of HCS in chlorobenzene, the solvent used in the phosgenation reaction reached 4.9%, which caused the boiling point of the solvent to rise from 132 °C to 143 °C, and the phosgenation reaction yield decreased from 99.5%.
  • the system began to show obvious blockage. After 9.5 months of operation, the system had to be stopped to discharge and replace the solvent, and the HCS substance in the solvent was removed.
  • This comparative example uses a phosgene synthesis device with by-product steam, uses high thermal conductivity composite activated carbon, and the filling method is not appropriate, and the content of high boiling point chlorinated hydrocarbons (referred to as HCS substances) slightly exceeds the standard.
  • HCS substances high boiling point chlorinated hydrocarbons
  • the high thermal conductivity composite activated carbon used in this example is prepared according to the following steps: mixing activated carbon powder, granular additives and adhesives in water to make a paste, drying and molding, and the drying conditions are placed under constant temperature and humidity conditions, and the temperature is 28 ° C. , humidity 5%, stand for 12h, and then carbonize with water vapor at 660°C for 6h to obtain the high thermal conductivity composite activated carbon; wherein the mass ratio of the granular additive and the activated carbon powder is 5:100, and the adhesive and The mass ratio of activated carbon powder is 10:100, the mass ratio of the activated carbon powder to water is 50:100, the adhesive is emulsified phenolic resin, and the granular additive is silicon carbide.
  • phosgene is prepared by using a phosgene synthesis device.
  • the hydrocarbons in the introduced CO are less than 1 ppm, the volume flow ratio of CO and chlorine is 100:94, and the phosgene synthesis operating temperature (that is, the phosgene synthesis reaction
  • the outlet temperature of the device) is 210 °C, the operating pressure is 3.1 barg, the high thermal conductivity composite activated carbon is filled in the tube, the diameter of the tube is DN38, the length of the tube is 5000mm, and the catalyst used is the high thermal conductivity composite activated carbon prepared above. ;
  • the catalyst loading area is divided into three sections from bottom to top.
  • the loading method is that the height of the first section is 1.0m, and 100wt% is filled with high thermal conductivity composite activated carbon.
  • the second section is 1.0m high, and 100wt% is filled with high thermal conductivity composite activated carbon. m, 100wt% loading of high thermal conductivity composite activated carbon.
  • the content of high-boiling point chlorinated hydrocarbons (HCS substances) in the phosgene produced by phosgene synthesis is detected to be 1100 ppm, and is continuously sent to the phosgenation reactor to react with MDA to generate MDI.
  • the solvent used in the phosgenation reaction is chlorobenzene.
  • the pressure of the gasification reaction is 3.2 barg
  • the maximum temperature of the phosgenation reactor is 135°C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA mass of the MDA solution (solvent is chlorobenzene) put into the reaction system The concentration was 30%, and the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • high thermal conductivity composite activated carbon is used, and the filling method is the same as that of Comparative Example 1, and there is no phenomenon that the content of high-boiling point chlorinated hydrocarbons (referred to as HCS substances) exceeds the standard.
  • HCS substances high-boiling point chlorinated hydrocarbons
  • the high thermal conductivity composite activated carbon used in this example is prepared according to the following steps: mixing activated carbon powder, granular additives and adhesive in water to make a paste, drying and molding, and the drying conditions are placed under constant temperature and humidity conditions, and the temperature is 25°C. , humidity 8%, stand for 18h, and then carry out constant temperature carbonization with water vapor at 650°C for 4h to obtain the high thermal conductivity composite activated carbon; wherein the mass ratio of the granular additive and the activated carbon powder is 5:100, and the adhesive and The mass ratio of activated carbon powder is 10:100, the mass ratio of the activated carbon powder to water is 50:100, the adhesive is emulsified phenolic resin, and the granular additive is silicon carbide.
  • phosgene is prepared by using a phosgene synthesis device.
  • the hydrocarbons in the introduced CO are less than 1 ppm, the volume flow ratio of CO and chlorine is 100:93, and the phosgene synthesis operating temperature (that is, the phosgene synthesis reaction
  • the outlet temperature of the device) is 205 °C, the operating pressure is 3.0 barg, the high thermal conductivity composite activated carbon is filled in the tube, the diameter of the tube is DN38, the length of the tube is 5000mm, and the catalyst used is the high thermal conductivity composite activated carbon prepared above , the inert agent uses alumina ceramic balls; the catalyst loading area is divided into three sections from bottom to top, the filling method is that the height of the first section is 1.5m, mixed with 75wt% alumina ceramic balls, 25wt% high thermal conductivity composite activated carbon, and the second section is 1.5m high.
  • the height of the section is 1.0m, mixed with 40wt% alumina ceramic balls and 60
  • the content of high-boiling point chlorinated hydrocarbons (HCS substances) in the phosgene produced by phosgene synthesis is detected to be 800 ppm, and it is continuously sent to the phosgenation reactor to react with MDA to generate MDI.
  • the solvent used in the phosgenation reaction is chlorobenzene.
  • the pressure of the gasification reaction is 3.2 barg
  • the maximum temperature of the phosgenation reactor is 135°C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA mass of the MDA solution (solvent is chlorobenzene) put into the reaction system The concentration was 30%, and the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • a high thermal conductivity composite activated carbon device is used, and the filling method is different from that of Example 1, and there is no phenomenon that the content of high boiling point chlorinated hydrocarbons (marked as HCS substances) exceeds the standard.
  • the high thermal conductivity composite activated carbon used in this example is prepared according to the following steps: mixing activated carbon powder, granular additives and adhesive in water to make a paste, drying and molding, and the drying conditions are placed under constant temperature and humidity conditions, and the temperature is 25°C. , humidity 8%, stand for 18h, and then carry out constant temperature carbonization with water vapor at 650°C for 6h to obtain the high thermal conductivity composite activated carbon; wherein the mass ratio of the granular additive and the activated carbon powder is 10:100, and the adhesive and The mass ratio of activated carbon powder is 10:100, the mass ratio of the activated carbon powder to water is 50:100, the adhesive is emulsified phenolic resin, and the particle additive is graphite.
  • phosgene is prepared by using a phosgene synthesis device.
  • the hydrocarbons in the CO introduced are less than 1 ppm, the volume flow ratio of CO and chlorine is 100:93, and the phosgene synthesis operating temperature is 200 °C (that is, light The outlet temperature of the gas synthesis reactor), the operating pressure is 3.0 barg, the activated carbon is packed in the tube, the diameter of the tube is DN50, the length of the tube is 5000mm, the catalyst used is the high thermal conductivity composite activated carbon prepared above, the inert agent Spherical silicon carbide is used; the catalyst loading area is divided into three sections from bottom to top, the filling method is that the height of the first section is 0.5m, mixed with 80wt% spherical silicon carbide and 20wt% high thermal conductivity composite activated carbon, and the height of the second section is 1.0m. Mixed with 40wt% spherical silicon carbide and 60wt% high thermal conductivity composite activated carbon, the height of
  • HCS substances high-boiling point chlorinated hydrocarbons
  • the solvent used in the phosgenation reaction is dichlorobenzene
  • the pressure of the phosgenation reaction is 5.1 barg
  • the maximum temperature of the phosgenation reactor is 145°C
  • the mass ratio of the pure phosgene and MDA participating in the reaction is 2.5
  • the MDA of the MDA solution put into the reaction system
  • the mass concentration was 30%
  • the phosgene concentration in the phosgene solution (the solvent was chlorobenzene) put into the reaction system was 70%.
  • a high thermal conductivity composite activated carbon device is used, and the filling method is different from that of Example 1, and there is no phenomenon that the content of high boiling point chlorinated hydrocarbons (marked as HCS substances) exceeds the standard.
  • the high thermal conductivity composite activated carbon used in this example is prepared according to the following steps: mixing activated carbon powder, granular additives and adhesive in water to make a paste, drying and molding, and the drying conditions are placed under constant temperature and humidity conditions, and the temperature is 26 ° C. , humidity 5%, stand for 23h, and then carbonize with water vapor at 680°C for 4h to obtain the high thermal conductivity composite activated carbon; wherein the mass ratio of the granular additive and the activated carbon powder is 7:100, and the adhesive and The mass ratio of activated carbon powder is 10:100, the mass ratio of the activated carbon powder to water is 45:100, the adhesive is activated clay, and the granular additive is alumina ceramic balls.
  • phosgene is prepared by using a phosgene synthesis device.
  • the hydrocarbons in the CO introduced are less than 1 ppm, the volume flow ratio of CO and chlorine is 100:94, and the phosgene synthesis operating temperature is 210 °C (that is, light The outlet temperature of the gas synthesis reactor), the operating pressure is 2.9barg, the activated carbon is packed in the tube, the diameter of the tube is DN25, the length of the tube is 5000mm, the catalyst used is the high thermal conductivity composite activated carbon prepared above, the inert Spherical silicon carbide is used; the catalyst loading area is divided into three sections from bottom to top.
  • the filling method is that the height of the first section is 1.0m, which is mixed with 80wt% spherical silicon carbide and 20wt% high thermal conductivity composite activated carbon, and the height of the second section is 2.0m. Mixed 60wt% spherical silicon carbide, 40wt% high thermal conductivity composite activated carbon, the height of the third section is 2.0m, all of which are high thermal conductivity composite activated carbon.
  • HCS substances high-boiling point chlorinated hydrocarbons
  • the solvent used in the phosgenation reaction is dichlorobenzene
  • the pressure of phosgenation reaction is 5.1barg
  • the maximum temperature of phosgenation reactor is 145 °C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA solution (solvent is dichlorobenzene) put into the reaction system is The mass concentration of MDA is 30%
  • the concentration of phosgene in the phosgene solution (solvent is dichlorobenzene) put into the reaction system is 70%.
  • a high thermal conductivity composite activated carbon device is used, and the preparation formula of the high thermal conductivity activated carbon is different from that of Example 1, and there is no phenomenon that the content of high boiling point chlorinated hydrocarbons (marked as HCS substances) exceeds the standard.
  • the high thermal conductivity composite activated carbon used in this example is prepared according to the following steps: mixing activated carbon powder, granular additives and adhesive in water to make a paste, drying and molding, and the drying conditions are placed under constant temperature and humidity conditions, and the temperature is 21 ° C. , humidity 3%, stand for 24 hours, and then carbonize with water vapor at 800°C for 2 hours to obtain the high thermal conductivity composite activated carbon; wherein the mass ratio of the granular additive and the activated carbon powder is 1.5:100, and the adhesive and The mass ratio of activated carbon powder is 10:100, the mass ratio of the activated carbon powder to water is 30:100, the adhesive is activated clay, and the granular additive is alumina ceramic balls.
  • phosgene is prepared by using a phosgene synthesis device, the hydrocarbons in the introduced CO are less than 1 ppm, the volume flow ratio of CO to chlorine is 100:95, and the phosgene synthesis operating temperature (that is, the phosgene synthesis reaction
  • the outlet temperature of the device) is 215°C, the operating pressure is 3.0barg, the activated carbon is filled in the tube, the diameter of the tube is DN25, the length of the tube is 5000mm, the catalyst used is the high thermal conductivity composite activated carbon prepared above, the inert agent Spherical silicon carbide is used; the catalyst loading area is divided into three sections from bottom to top, the filling method is that the height of the first section is 2.0m, mixed with 80wt% spherical silicon carbide and 20wt% high thermal conductivity composite activated carbon, and the height of the second section is 2.0m. 60wt% spherical silicon carbide and 40wt% high thermal conductivity composite activated carbon are mixed
  • HCS substances high-boiling point chlorinated hydrocarbons
  • the solvent used in the phosgenation reaction is dichlorobenzene
  • the pressure of phosgenation reaction is 5.1barg
  • the maximum temperature of phosgenation reactor is 145 °C
  • the mass ratio of pure phosgene and MDA participating in the reaction is 2.5
  • the MDA (solvent is dichlorobenzene) of the MDA solution put into the reaction system ) mass concentration is 30%
  • the phosgene concentration in the phosgene solution (solvent is dichlorobenzene) put into the reaction system is 70%.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

La présente invention concerne un procédé de préparation de MDI et un procédé de préparation de phosgène. Le procédé de préparation de MDI selon la présente invention comprend : la soumission, en présence d'un solvant, d'une charge d'alimentation de phosgène et du MDA à une réaction de phosgénation dans un réacteur de phosgénation pour générer des produits de réaction comprenant le MDI et le chlorure d'hydrogène, et l'évacuation du chlorure d'hydrogène du réacteur de phosgénation en tant que phase gazeuse évacuée pour réguler la teneur en masse d'impuretés d'hydrocarbure chloré à point d'ébullition élevé contenues dans la charge d'alimentation de phosgène pour que la réaction de phosgénation soit inférieure à 1000 ppm, les impuretés d'hydrocarbure chloré à point d'ébullition élevé étant des hydrocarbures chlorés saturés et/ou insaturés ayant deux atomes de carbone. Le procédé de préparation de MDI selon la présente invention a une stabilité de traitement améliorée.
PCT/CN2020/113112 2020-09-03 2020-09-03 Procédé de préparation de mdi et procédé de préparation de phosgène WO2022047681A1 (fr)

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CN102317255A (zh) * 2008-11-26 2012-01-11 亨茨曼国际有限公司 制备异氰酸酯的方法
EP1890998B1 (fr) * 2005-05-30 2014-02-26 Huntsman International Llc Procede de preparation de polyisocyanates de la serie diphenylmethane
CN104415770A (zh) * 2013-08-26 2015-03-18 万华化学集团股份有限公司 一种制备光气的催化剂及制备光气的方法
CN110449147A (zh) * 2019-08-09 2019-11-15 万华化学集团股份有限公司 一种用于光气合成的催化剂及其制备方法和应用
CN111995549A (zh) * 2020-09-03 2020-11-27 万华化学集团股份有限公司 制备mdi的方法和光气制备方法

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US6500984B1 (en) * 2001-04-30 2002-12-31 General Electric Company Method for producing phosgene
EP1890998B1 (fr) * 2005-05-30 2014-02-26 Huntsman International Llc Procede de preparation de polyisocyanates de la serie diphenylmethane
CN101348252A (zh) * 2008-04-25 2009-01-21 甘肃银光化学工业集团有限公司 甲苯二异氰酸酯生产工艺中光气的回收方法
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CN104415770A (zh) * 2013-08-26 2015-03-18 万华化学集团股份有限公司 一种制备光气的催化剂及制备光气的方法
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* Cited by examiner, † Cited by third party
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CN114920668A (zh) * 2022-05-13 2022-08-19 万华化学集团股份有限公司 一种制备低氯代杂质异氰酸酯的方法
CN114920668B (zh) * 2022-05-13 2023-10-13 万华化学集团股份有限公司 一种制备低氯代杂质异氰酸酯的方法

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